After 4 Years Of Fighting - C&RT Settle Out Of Court

[Arthur Marshall]

 

And, of course [i hope], you were not counting me as bolshy either.

Nor was I! I was just pointing out that some of us can fight legal stuff with the best (and worst) of them. It's so easy to be misunderstood...

[Mike Todd]

Some of the difficulty lies in the rather sparse statement in the minimum standard document which does not have the common qualifier of a reasonableness test. Almost every lock has a wall that is not polished smooth and hence, at least in the way in which it has been used in this thread, constitute a breach of the standard. In any event, however smooth the wall, the top edge will always be a possible cause of hang up when descending as most boats have rubbing strakes/gunnels that are the widest point and may just catch - it did happen to me a very long time ago in a boat where this was a more pronounced feature than usual.

 

It seems to me that the minimum standard is really unhelpful unless there is some conditional to it. Of course, many people would have difficulty in accepting or understanding such a condition (it is always much easier to believe in a world of absolutes). Equally, it is open to manipulation by those responsible for maintenance or the budget policy since it can be 'adjusted' in the event that resources have to be reduced.

 

However, if set at a realistic level it would help to highlight the smaller number of cases which are a priority above those where the unevenness is just a fact of life or where a clear warning is sensible (as for example at Beeston Iron Lock where no amount of maintenance short of a re-build - which the heritage people would probably disallow anyway - )

[Chris_marigold]

Another thing which I don't think has been mentioned is the way modern narrowboats are constructed. They're basically welded out of flat plates of steel with sharp corners that catch very easily on any protrusion. And the design is such a boat has only to be tipping a couple of degrees for it to start flooding aft and then sinking can happen very suddenly.

 

The last time I went up Bank Newton (I've never been down) I was in my Dutch barge which is just the opposite. Apart from the rubbing strake and similar protrusions it has nothing that would catch. And you could probably tip it 10 degrees before it would start flooding.

 

Is there any way to force manufacturers to go back to the older designs with rounded corners? Obviously it costs a bit more but it's a lot cheaper than reconstructing hundreds of locks.

 

Chris

[alan_fincher]

And the design is such a boat has only to be tipping a couple of degrees for it to start flooding aft and then sinking can happen very suddenly.

 

This point is lost on me, I'm afraid.

 

Even the poorer modern design narrow boats surely have a fair margin of tolerance to being "tipped", (whether that means being rolled sideways, or an end being higher or lower than it should be), before anything too dramatic happens.

 

Any boat that it is sensitive to something going wrong when it is "tipped" by only a few degrees surely has some fairly serious issues.

 

I'm not trying to play anything down here, just to understand the point you are trying to make.

 

I am well aware, having now seen or experienced it a few times, that when things do start to go wrong, it can all get quite dramatic and quite frightening really very quickly. But usually, (in my experience) by the time you are at that stage, a boat can be well heeled over, or bow or stern high or low, and still not yet have water pouring in.

 

I must admit I have tried to re-read several times the description of the original incident here, and still remain somewhat unclear about what the circumstances were that allowed the boat to be engulfed so completely and suddenly. The description seemed to be of a fairly cautious operation of the lock, where the problem was spotted quite quickly, but still dropping paddles quickly does not seem to have been enough, which, clearly in 90 something percent of similar cases it probably would be, without getting as far as a sinking.

[Horace42]

 

This point is lost on me, I'm afraid.

 

Even the poorer modern design narrow boats surely have a fair margin of tolerance to being "tipped", (whether that means being rolled sideways, or an end being higher or lower than it should be), before anything too dramatic happens.

 

Any boat that it is sensitive to something going wrong when it is "tipped" by only a few degrees surely has some fairly serious issues.

 

I'm not trying to play anything down here, just to understand the point you are trying to make.

 

I am well aware, having now seen or experienced it a few times, that when things do start to go wrong, it can all get quite dramatic and quite frightening really very quickly. But usually, (in my experience) by the time you are at that stage, a boat can be well heeled over, or bow or stern high or low, and still not yet have water pouring in.

 

I must admit I have tried to re-read several times the description of the original incident here, and still remain somewhat unclear about what the circumstances were that allowed the boat to be engulfed so completely and suddenly. The description seemed to be of a fairly cautious operation of the lock, where the problem was spotted quite quickly, but still dropping paddles quickly does not seem to have been enough, which, clearly in 90 something percent of similar cases it probably would be, without getting as far as a sinking.

Like I said in #107, how much time have you got to take remedial action to save the boat from the point of time you realise something very serious is obviously wrong - where from the moment of realisation, I would not be surprised if it was not already too late - and it thus in panic becomes a life-saving exercise.

[NigelMoore]

Is there any way to force manufacturers to go back to the older designs with rounded corners? Obviously it costs a bit more but it's a lot cheaper than reconstructing hundreds of locks.

 

Bring back Springers? Of course, there is still the flat bottom plate section aft, but at least that is only an inch or so below waterline - I have been caught up on a protruding large spike in a crowded Thames lock and had time to scream to the lock keeper to stop, though I slipped off as he came to investigate. There was just enough room for the necessary sideways movement.

[Chris_marigold]

 

Any boat that it is sensitive to something going wrong when it is "tipped" by only a few degrees surely has some fairly serious issues.

 

 

2 degrees on a 60' boat corresponds to 2 feet. Now I haven't worked out all the hydrostatics and it may be the front of the boat needs to be lifted twice that, but I'm assuming that the back of the boat will go down by about the same amount. The freeboard at the stern is maybe 18". So it only takes a little for the water to start pouring into the engine compartment, which is not waterproof in the typical narrowboat.

 

Once the water starts pouring in it adds to the moment that is tipping the boat over and it will soon be unstoppable even if the water level doesn't go down any more. So you first have to close the bottom sluices and then go to the other end of the lock to open the top gates to start correcting the water level. That takes quite a few seconds or probably rather more than a minute.

 

In this accident there was a complicating factor of a young girl in the cabin (with the front door locked). By the time Ken's wife had gone in to fetch her and try to get her out of the back door it was impassible due to the water. If Ken hadn't had the presence of mind to leave the winding, smash the side window and get them out they would both have been drowned.

 

I think that is the reality with most narrowboats today.

 

Chris

[Mike Todd]

 

2 degrees on a 60' boat corresponds to 2 feet. Now I haven't worked out all the hydrostatics and it may be the front of the boat needs to be lifted twice that, but I'm assuming that the back of the boat will go down by about the same amount. The freeboard at the stern is maybe 18". So it only takes a little for the water to start pouring into the engine compartment, which is not waterproof in the typical narrowboat.

 

Once the water starts pouring in it adds to the moment that is tipping the boat over and it will soon be unstoppable even if the water level doesn't go down any more. So you first have to close the bottom sluices and then go to the other end of the lock to open the top gates to start correcting the water level. That takes quite a few seconds or probably rather more than a minute.

 

In this accident there was a complicating factor of a young girl in the cabin (with the front door locked). By the time Ken's wife had gone in to fetch her and try to get her out of the back door it was impassible due to the water. If Ken hadn't had the presence of mind to leave the winding, smash the side window and get them out they would both have been drowned.

 

I think that is the reality with most narrowboats today.

 

Chris

Are you conflating the issues with cilling and those with catching on lock sides?

[Graham Davis]

 

2 degrees on a 60' boat corresponds to 2 feet. Now I haven't worked out all the hydrostatics and it may be the front of the boat needs to be lifted twice that, but I'm assuming that the back of the boat will go down by about the same amount. The freeboard at the stern is maybe 18". So it only takes a little for the water to start pouring into the engine compartment, which is not waterproof in the typical narrowboat.

 

Once the water starts pouring in it adds to the moment that is tipping the boat over and it will soon be unstoppable even if the water level doesn't go down any more. So you first have to close the bottom sluices and then go to the other end of the lock to open the top gates to start correcting the water level. That takes quite a few seconds or probably rather more than a minute.

 

In this accident there was a complicating factor of a young girl in the cabin (with the front door locked). By the time Ken's wife had gone in to fetch her and try to get her out of the back door it was impassible due to the water. If Ken hadn't had the presence of mind to leave the winding, smash the side window and get them out they would both have been drowned.

 

I think that is the reality with most narrowboats today.

 

Chris

 

I think you need to do your maths again!

 

2 degrees is 1:45, and 1/45th of 60ft is 16".

 

And your example shows how ill-prepared and at error the boat owner was leaving, the front door locked whilst someone was in the boat, plus that "story" seems to have little or no relevance to the OP.

Edited January 14, 2017 by Graham Davis

[Chris_marigold]

Are you conflating the issues with cilling and those with catching on lock sides?

 

No, it's a very similar issue from that point of view. Except that with cilling it's the prow of the boat that's dipping in the water and that is probably more resistant to being dunked than the stern. Remember that in this case the ledge was within a few feet of the bottom gate so it was caught close to the prow.

[Alan de Enfield]

 

I think you need to do your maths again!

 

2 degrees is 1:45, and 1/45th of 60ft is 16".

 

And your example shows how ill-prepared and at error the boat owner was leaving, the front door locked whilst someone was in the boat, plus that "story" seems to have little or no relevance to the OP.

 

I am not following your maths - what I am I doing wrong ?

 

1:45 = 1.27^o

1:28 = 2.0^o

1/28th of a 60 foot boat is 25 inches (or a tad over 2 feet)

 

Edit to add : Entirely agree, all exits should be unlocked and available at all times when anyone is on board.

Edited January 14, 2017 by Alan de Enfield

[Chris_marigold]

 

I think you need to do your maths again!

 

2 degrees is 1:45, and 1/45th of 60ft is 16".

 

 

It's your maths that needs a little brushing up! Where did you get that formula from?

 

atan(2/60) = 1.90915

 

Anyway I allowed myself 100% error, so it makes little difference.

[Chewbacka]

This right ????

 

Tan 2 degrees = 0.0349

 

60ft * 0.0349 = 2.09 ft

 

So a 60ft boat at 2 degrees slope would be about 2ft low at one end.

[MtB]

 

I am not following your maths - what I am I doing wrong ?

 

1:45 = 1.27^o

1:28 = 2.0^o

1/28th of a 60 foot boat is 25 inches (or a tad over 2 feet)

 

Edit to add : Entirely agree, all exits should be unlocked and available at all times when anyone is on board.

 

 

 

I totally disagree. No-one should be inside a NB when transiting a lock.

Deaths from drowning trapped inside a sunken boat in a lock keep happening. Will no-one ever learn? Isn't the risk obvious?

[Chris_marigold]

I totally disagree. No-one should be inside a NB when transiting a lock.

Deaths from drowning trapped inside a sunken boat in a lock keep happening. Will no-one ever learn? Isn't the risk obvious?

 

Ok, smart alec. You have a 5 year old child. At every lock you tell her to get out of the boat and stand quietly on the bank while you busy yourself with the lock. Oh, yes, you tie her to a bench to make sure she doesn't fall in or wander off with a stranger or...

 

If I was doing a risk assessment, I know which option would come out worse.

 

Oh, and that happened to be one of the requests that Ken made for a sign at this particular lock and CRT refused to agree to it.

[Paul C]

This right ????

 

Tan 2 degrees = 0.0349

 

60ft * 0.0349 = 2.09 ft

 

So a 60ft boat at 2 degrees slope would be about 2ft low at one end.

 

 

Well its sin 2deg, although they are very similar at low values. BUT the boat will pivot in the middle, so the front would be 1 foot higher and the back would be 1 foot lower. And if you refine the place it pivots, you'd probably say its more to the rear of the boat than the front (boat is heavier at rear with the engine), thus making it less than 1 foot lower at the back.

[Chewbacka]

 

Ok, smart alec. You have a 5 year old child. At every lock you tell her to get out of the boat and stand quietly on the bank while you busy yourself with the lock. Oh, yes, you tie her to a bench to make sure she doesn't fall in or wander off with a stranger or...

 

If I was doing a risk assessment, I know which option would come out worse.

 

Oh, and that happened to be one of the requests that Ken made for a sign at this particular lock and CRT refused to agree to it.

Agree - Too easy to consider able bodied adults only when making rules.

The risks of getting disabled people and very young children on and off boats at every lock and keeping them safe, including in inclement weather is much greater than leaving then on board and being vigilant whilst operating locks.

[Allan(nb Albert)]

 

 

 

I totally disagree. No-one should be inside a NB when transiting a lock.

Deaths from drowning trapped inside a sunken boat in a lock keep happening. Will no-one ever learn? Isn't the risk obvious?

C&RT produced two reports for HSE into the incident. They stated as a fact that nobody has died inside a sunken narrowboat in a lock since 1998.

 

Since that report, I believe there has been one further fatality.

 

I don't think a 17 years gap between fatalities is keeps happening.

[Alan de Enfield]

 

 

Well its sin 2deg, although they are very similar at low values. BUT the boat will pivot in the middle, so the front would be 1 foot higher and the back would be 1 foot lower. And if you refine the place it pivots, you'd probably say its more to the rear of the boat than the front (boat is heavier at rear with the engine), thus making it less than 1 foot lower at the back.

 

In my simple mind, that is correct if the point to pivot is 'free', however if the bow is 'clamped' between another boat and the side wall, surely the pivot point becomes a 'fixed' point, so the bow remains in the same (fixed) position and at a 2^othe back end is 25" lower.

 

Consider a bow line being tied off - the 'pivot' point is the bow.

Consider a stern line being tied off - the pivot point becomes the stern.

[Chewbacka]

 

 

Well its sin 2deg, although they are very similar at low values. BUT the boat will pivot in the middle, so the front would be 1 foot higher and the back would be 1 foot lower. And if you refine the place it pivots, you'd probably say its more to the rear of the boat than the front (boat is heavier at rear with the engine), thus making it less than 1 foot lower at the back.

I wondered if Sine was better than Tan, but at very small angles the are about the same (at least to an engineer they are, probably not to a mathematician ) so I used Tan.

 

As to the pivot point, if the boat is caught on a ledge or cill at one end, then the pivot point is fixed, and that is one of the reasons why boats can sink quickly as the far end will be 2ft low for 2 degree slope leading to rapid flooding.

C&RT produced two reports for HSE into the incident. They stated as a fact that nobody has died inside a sunken narrowboat in a lock since 1998.

 

Since that report, I believe there has been one further fatality.

 

I don't think a 17 years gap between fatalities is keeps happening.

I think the latest fatality was on the Droitwich canal, and from memory the person that drowned got back onto the boat to retrieve some items, so not really related to this argument of being off the boat in locks.

[Jim Riley]

 

 

 

I totally disagree. No-one should be inside a NB when transiting a lock.

Deaths from drowning trapped inside a sunken boat in a lock keep happening. Will no-one ever learn? Isn't the risk obvious?

you're a single (handed) boater?

[alan_fincher]

I totally disagree. No-one should be inside a NB when transiting a lock.

Deaths from drowning trapped inside a sunken boat in a lock keep happening. Will no-one ever learn? Isn't the risk obvious?

 

Keep happening?

 

Really?

 

Would you care to list all that have happened in (say) the last 10 years?

 

(You can't count ones where people weren't initially inside, but decided to go back in to try and rescue something important though!)

[Chris_marigold]

 

 

Well its sin 2deg, although they are very similar at low values. BUT the boat will pivot in the middle, so the front would be 1 foot higher and the back would be 1 foot lower. And if you refine the place it pivots, you'd probably say its more to the rear of the boat than the front (boat is heavier at rear with the engine), thus making it less than 1 foot lower at the back.

 

Yes agree on the sin: it makes one-hundredth of an inch difference

And you're right on the angle of the boat: when the stern is 2 feet below, the angle will be 4 degrees because the centre of the boat will stay the same with respect to the water level. Where it pivots is purely dependent on the balance of the boat and I don't think it would make much difference.

 

But if you think about how much the water level has to drop to cause that, it's still only 2 feet. That's a quarter of the total fall of many locks and it can happen mighty quick. And 4 degrees still isn't much to detect by eye. Ok, a 4' difference between stem and stern is more pronounced but remember all the things that are usually happening at the time and from some angles it may not be so obvious.

[Paul C]

 

In my simple mind, that is correct if the point to pivot is 'free', however if the bow is 'clamped' between another boat and the side wall, surely the pivot point becomes a 'fixed' point, so the bow remains in the same (fixed) position and at a 2^othe back end is 25" lower.

 

Consider a bow line being tied off - the 'pivot' point is the bow.

Consider a stern line being tied off - the pivot point becomes the stern.

 

 

I wondered if Sine was better than Tan, but at very small angles the are about the same (at least to an engineer they are, probably not to a mathematician ) so I used Tan.

 

As to the pivot point, if the boat is caught on a ledge or cill at one end, then the pivot point is fixed, and that is one of the reasons why boats can sink quickly as the far end will be 2ft low for 2 degree slope leading to rapid flooding.

 

 

Imagine a boat with its front fender caught in the gate as the lock drains. The front pivot point is indeed fixed, but there's 2 points where the boat is supported. The pivot at the front is fixed, but as the water drains the other pivot point is the buoyancy of the water, around the middle of the boat, where the level of the water doesn't really vary. Because the height of each pivot is changing, when the water drains 1 foot, the front is 1 foot higher than the water level and the front of the boat is in the air. The back is 1 foot deeper in the water (2 foot overall....but the water level isn't the same as before).

[Alan de Enfield]

 

 

 

Imagine a boat with its front fender caught in the gate as the lock drains. The front pivot point is indeed fixed, but there's 2 points where the boat is supported. The pivot at the front is fixed, but as the water drains the other pivot point is the buoyancy of the water, around the middle of the boat, where the level of the water doesn't really vary. Because the height of each pivot is changing, when the water drains 1 foot, the front is 1 foot higher than the water level and the front of the boat is in the air. The back is 1 foot deeper in the water (2 foot overall....but the water level isn't the same as before).

 

I think I understand what you are saying, but, surely the 'buoyancy pivot point' must move backwards to compensate for the effective 'shortening of the boat' (that is still in the water)

 

It must get to the point where the buoyancy pivot point can no longer support the boat as the angle gets steeper then more of the stern of the boat will be submerged - otherwise a boat could stand on its end and still float